The sodium bicarbonate co-transporter, hereinafter called "Na+/HCO3-- co-transporter", is one of the mechanisms involved in the regulation of intracellular pH. Acidosis established during myocardial ischemia stimulates this system. Extrusion of protons through Na+/HCO3--co-transporter is accompanied by cellular uptake of Na+ leading to more dangerous Ca2+ overload due to the functioning of Na+/Ca2+ exchanger in reverse-mode. This implies that specific inhibition of Na+/HCO3--co-transporter will be of benefit in reduction of cellular injury during ischemia.
A human kidney sodium bicarbonate transporter (NBC) has recently been described (Burnham et al., J Biol Chem, 272; 19111-19114, 1997). In addition, an electrogenic Na+ bicarbonate cotransporter of Ambystoma tigrinum has also been recently described (Romero et al., Nature, 387; 409-413, 1997).
This suggests that members of the sodium bicarbonate co-transporter family may have potential use as therapeutic targets. Consequently there is a need for identification and characterization of further members of the sodium bicarbonate co-transporter family which may play a role in preventing, ameliorating or correcting dysfunctions or diseases, including, but not limited to, ischaemia heart disease, arrhythmias, congestive heart disease, stroke and renal failure,